Wednesday, January 8, 2014

Kactus Kicker: Recent Progress

This article gives some of the history behind,  and then illustrates some of the recent development work I have done,  on the wheeled version of my “Kactus Kicker” cactus control tool.  Before offering this option again routinely,  I have to simplify and revise it into something a little more producible. 
It was originally a separate design worked out mostly by my friend Dave Gross,  who was doing cactus eradication as a commercial service,  before he recently retired.  We called it the “commercial grade tool”,  as distinct from the then-much lighter-built,  no-wheels “homeowner grade tool”.  That distinction between the two designs is no more.
As my development work proceeds,  I will add updates to the end of this article. 
History
My original write-ups about cactus control are on a sub-page at the http://www.txideafarm.com site,  which has not been recently updated.  The descriptions and photos of how it works that are posted there are nevertheless still very good,  since nothing about that process has changed.  The older hardware photos posted there show quite a difference between the "homeowner-grade" and "commercial-grade" tools,  something that has since changed very substantially since then
As Dave originally built them (mostly at my shop),  the "commercial grade" tool was bigger,  heavier,  and tougher,  and had transport wheels which were hydraulically,  electrically,  or mechanically (manually) actuated.  Today,  I use exactly the same tough chassis for both versions,  so there is no longer a “commercial tool” distinct from the “homeowner tool”,  there is only the “Kactus Kicker” and a suite of options.  The transport wheel assembly and the tow-bar hitch assembly are simply two among many options that can now be added at extra cost. 

The wheels allow easier load onto a trailer,  with a trailer-mounted electric winch,  if you lack a lift bucket on your tractor.  The wheels also allow you to easily and quickly "step over" a bale of debris,  if such a thing accumulates underneath your tool in the field.  That second advantage is really the more important one.  Wheeled tools today are pretty near 1000 pounds each,  and a whole lot more expensive.  Today,  I only offer the wheeled option as hydraulically-operated,  since that is the most practical option with most recent-vintage farm tractors.  (Electrical is slow,  and mechanical saves no labor at all.) 

The tool rigged with wheels is something I am currently still improving and experimenting with,  before I offer it for sale again.  (Illustrating progress toward that goal is the point of this article.)  I need to finish re-working and re-testing my revised experimental hydraulic prototype,  before I finalize its design and its price.  But,  I believe it will price-out in the neighborhood of $5000 each at my shop (update 4-15-14:  $7000).  There is a lot more steel,  a whole lot more hand-work labor,  and a whole lot of really-expensive hydraulic parts,  that all go into a wheeled tool.  Those I only offer to specific customer order,  half the money up-front.  Update 3-21-16:  for actual prices,  see the new website http://www.killyourcactusnow.com,  these numbers are inaccurate.

The plain tool is 8 feet wide,  and weighs pretty near 720 pounds,  as I build them today.  For both versions,  the basic deck is 2 feet by 8 feet.  It has a “barge front” on the front edge to help it wedge its way over rock outcrops and other obstructions,  up to about 6 inches relief above surface.  There is a stabilizing snout projecting forward from the middle of the front edge.  Stable tow is from the corners of the main deck,  however. 
Today I build this stabilizing snout very stout,  even on the plain tool,  because so many customers have such rough,  rocky ground to take care of.  The wheeled tool needs a slightly-longer snout with an extra skid plate,  otherwise,  both versions now use the same basic snout design. 
You can see how the plain tool is built in “Construction of the Plain Cactus Tool”,  posted 10-12-2013,  right here on “exrocketman”.  I have changed the details of the snout tie-down brackets and the chain towers since then,  but today those components are exactly the same as what I used on the experimental wheeled tool shown in this article. 
Availability
Plain tools I build speculatively in pairs every so often.  Once I have steel available,  there's about a week's worth of piecepart fabrication,  before I am ready to call my professional welder and have him "stitch" them together.  His work schedule is the real driving factor,  which is not under my control.  Once he is done,  I paint them and rig them,  and they are ready to sell.  This next batch is priced at $2000 each,  here at my shop on the farm near McGregor,  Texas.  Update 3-21-16:  for actual prices,  see the new website http://www.killyourcactusnow.com,  these numbers are inaccurate.

The new,  revised wheeled tools are not yet available for sale,  but soon will be.  These will be built only to specific customer order,  half the money up-front.  Update 3-21-16:  both the plain tool and the hydraulic tool are available.  For options and prices,  see http://www.killyourcactusnopw.com.  
How Employed
The cactus tool (wheeled or plain) is a drag implement that you pull at walking speed on a chain bridle behind a tractor.  It breaks off the above ground cactus foliage,  runs over it instead of just pushing it around,  and thereby crushes it with the weight of the tool.  Cactus foliage damaged like this will bleed out dry,  and die,  before it can successfully put down new roots from the thorn sites on the pads.  

If you just push the pads around (as in “blading” and “chaining”),  much of the stuff you tore loose will just re-root and create more cactus plants.  You end up just spreading the cactus and making your problem worse,  if you don't do this right and crush thoroughly what you tear loose.  The same thing applies to shredding:  the shredder or mower blade cuts are just not enough damage. 

Either version is stout enough to last a very long time.  The big tough snout and large barge front are there precisely to wedge themselves over fixed rocky outcrops up to about 6 inches relief.  You can pretty well run over trash trees and brush,   up to about an inch and a half diameter,  one (or at most two) at a time.  Loose rocks that move when you hit them can be run over up to about 10 inches size,  although stuff like that can hang up under the tool.  If it does hang up,  and you have a plain tool,  stop,  slack the tow chain,  pry up the tool,  and remove the offending object.  If you have a wheeled tool,  just lower the wheels and “step over” it.  The same processes apply to clearing debris bales. 
These tools in either form can handle moderately rocky ground,  but you should definitely go around the bigger obstacles,  stuff that would cause you to hang up completely.  You are towing on a chain,  which has no "give",  meaning a piece of steel somewhere is going to break,  if you do hang up.  I deliberately build these with smaller chain,  so as to try to ensure the chain breaks first.  Chain is a whole lot easier to repair or replace than any of the rest of the steel in the tools,  or the hitches on the tractors towing them. 
Typical tow loads on level ground would average around a half a ton per tool,  maybe up to a ton,  which can act almost dead sideways in a tight turn.  That’s around 8-16 drawbar horsepower per tool,  at 3 mph tow speed.  In really rocky country,  or on steeper slopes,  or in really dense cactus,  tow loads (and power required) are even higher.  If you are towing from a 3-point rig instead of a plain drawbar,  be sure it is braced for side loads of that magnitude,  or you will break it. 
One thing to remember about wedging your way with the barge front over multiple smaller outcrops at once,  is that the tool is the "hammer" and the Earth is the "anvil".  A tool wedged up in the air is not down upon the ground crushing cactus.  If you instead drag right alongside such obstructions from multiple directions,  it will take more time,  but this is far more effective at tearing loose and crushing the cactus. 
These tools are no panacea:  there is serious work involved.  But,  the advantage of all-mechanical eradication is twofold:  (1) I converted this to nothing but mostly “driving-a-tractor” work,  and (2) there really is an end to it,  unlike herbicide spraying.  And,  you can combine it with herbicide spraying if you want to.  (You’ll reach that final eradication point sooner,  if you do.  You’ll just spend more money for herbicide to save the additional time.)  With herbicide alone,  there is only control,  and there is no end to it.  You will be buying herbicide and spraying about every 2-3 years,  “forever”. 

Typically,  with either version of the tool,  what you do is select a small area like 5 acres,  and you drag the tool as many times as is needed through the cactus to tear loose and crush everything you can reach,  knowing full well that you will not kill everything (“first treatment”).  You do this again (“second treatment”) about 3 to 6 months later,  but there will be a whole lot less cactus to kill.  You do it a third time (“third treatment”) about 3 to 6 months later again,  and this may well be motoring from plant-to-plant in very sparse growth,  instead of area coverage.  Every place is different,  however. 

After the three treatment sequence,  you kill the “ones-and-twos” regrowth from the roots (only the big roots will re-sprout) by motoring from plant-to-plant.  Do that every 6 months to a year,  for about 2-3 years,  and the roots will finally starve to death in the ground,  for lack of green photosynthetic pads above.  Then,  it is all gone.  That’s “follow-up”,  and it is required,  or the cactus will eventually re-grow from the buried roots. 

You can clear cactus out of fencelines with a hoe,  and drag it out from the fence a bit.  Then run over the hoeings with the cactus tool to crush and kill them,  so that they do not re-root.  This works whether you have wheels or not.  Same thing applies to clumps of cactus hidden in among dense brush or trees. 
Reworking the Wheeled Tool Design

When Dave retired,  he sold off his 5 cactus tools and other associated equipment.  All of that is now gone.  So,  I built a dedicated experimental prototype for myself,  based on the best of his tools,  but also incorporating some ideas of my own aimed at better producibility.  This doesn’t always work as intended,  so my prototype is a work-in-progress.  Again,  watch below for updates appended at this article’s end.

I initially incorporated three changes:  (1) a substantially-revised hydraulic wheel assembly,  (2) revised chain towers,  and (3) a new snout adapted from the current plain tool.  Not long after building it,  I added a possible tow-bar hitch rig as a fourth change.  The revised wheel assembly was simpler and much lighter than the approach Dave had used,  which let me go to fixed ballast weight on the tool deck,  in common with the plain design. 

The revised snout design was also simpler and much lighter (yet far stiffer in twisting),  which moved more of the tool’s weight aft onto the crush rail at the rear.  This unloaded a great portion of the weight from the snout slider plate,  which let me use a smaller slider plate than Dave had to use.  Although,  I am thinking of offering larger slider plates as an option for those who have soft,  sandy land.  Those would need prototype testing,  too. 

So,  the common chassis became the deck and crush rail,  plus skids,  plus fixed ballast,  and the same barge front and brace system.   The wheel assembly and the slightly-longer snout weld to that common chassis.  There’s not much need for a tow bar hitch if you have the plain tool,  so it is only offered for wheel-equipped version.  (The other options can be added to either version.) 

The real differences thus became only the wheel assembly and hydraulics as an option added to the same common chassis,  and a slightly-longer snout with the extra skid plate,  for smooth sliding when the wheels are down.  The other difference is the tow bar hitch assembly,  which is still currently far from being market ready,  but which will be an add-on option that not everybody will need,  even if they do want the wheel assembly. Update 4-15-14:  towbar hitch has been revised to something practical,  durable,  and producible,  on the experimental prototype.  Update 3-21-16:  Towbar hitch is a standard option available on the hydraulic tool only (plain tool does not need it),  see http://www.killyourcactusnow.com.

Other options will include trailer hitch points that can be added to the aft deck,  heavier-grade chains,  and fences for retaining equipment left stored on the tool’s deck,  against its rattling-off while underway.  Other than the heavier chains,  I haven’t prototyped these yet.  Not everybody will need them,  either. 

So,  the basic common chassis assembly is identical to that of the plain tool.  The difference shows up when the snout is constructed.  There is a 15 degree fabrication shim needed for jigging-up and welding the second slider plate.  See figures 1 (4073),  2 (4075) and 3 (4076).  The basic common chassis also includes the barge front braces,  as shown in figure 4 (4079).  Once the snout is welded in place,  you add the barge front pieces,  resting them upon the projecting skids while you weld them in place butted against the braces and snout,  as shown in figures 5 (4080) and 6 (4081).  

Figure 1 (photo 4073) – Common Chassis Being Built

Figure 2 (photo 4075) – Longer Snout Being Built

Figure 3 (photo 4076) – Shim Under Snout During Fabrication

Figure 4 (photo 4079) – Adding Barge Front Braces

Figure 5 (photo 4080) – Barge Front Rests on Skids

Figure 6 (photo 4081) – Barge Front Welds to Braces and to Snout

For the wheeled version,  the longer snout needs shear tabs added at both ends,  as shown in figures 7 (4084) and 8 (4085).  The plain version only needs shear tabs at the aft end,  where it mounts to the tool deck.  The new triangular plate snout brackets are clearly shown in these photos.  These new brackets replace the older-style brackets made of angle stock.  They are at least as strong as the older design,  and cut a lot of labor from both the piecepart fabrication and the welding. 

Figure 7 (photo 4084) – Aft Shear Tabs (one each side,  both versions)

Figure 8 (photo 4085) – Forward Shear Tabs (one each side,  wheeled only)

The prototypes for the new chain towers are shown in figure 9 (4088).  These are made of channel stock,  and calculate as far stronger than the older gusseted-tube design.  These are good enough to break the heaviest chain I plan to offer.  For production,  I replaced the flat-plate tops with channel,  which controlled the weld distortion evident in the prototype photo.  This new chain tower design has been standard in production since serial number 055.  

Figure 9 (photo 4088) – New Chain Tower Design

I rigged this prototype tool with the same chain bridle as is used on production plain tools,  just a slightly-longer piece to accommodate the slightly-longer snout.  It has the same kind of cross chain,  as shown in figure 10 (4092).  This serves to limit pitching and yawing motions on very rough ground.  More importantly,  the cross chain allows you to convert the tow bridle to a lift sling,  with nothing more than one single bolt,  which is included with all production tools sold.  

Figure 10 (photo 4092) – Chain Tow Bridle Installation

Figure 11 (4096) shows my initial hydraulic wheel installation.  Unlike Dave,  I mounted two struts with a clevis hinge,   on the deck atop the ballast bar aft and atop spacers forward.  I used his original 24 inch spacing for this.  The same kind of struts also formed the wheel assembly itself.  My first version used lighter-duty solid wheelbarrow wheels on a narrow-gage spacing,  but with the same diameter as the heavy solid shredder wheels that go on a production design.  

Figure 11 (photo 4096) – Narrow-Stance Hydraulic Wheel Strut Assembly

The main difference from Dave’s version is that I moved the hinge line off-board aft of the tool deck.  This allowed me to use lighter,  simpler,  easier-to-build,  and less vulnerable straight legs.  By carefully arranging the actuating arm geometry,  I was also able to maintain a far lower equipment profile over the deck with the wheels retracted.  This allows better clearance when working around dense brush and trees.  

The only problem with this narrow-stance design proved to be too much “wobbling instability” wheels-down rolling over rough terrain.  (The next version is a re-work of the same basic design,  just to a wider stance.)  I had a clever axle-and-spacer design that allowed me to use a single key to retain the wheels,  as depicted in figure 12 (4097).  But,  this kind of narrow design proved unsuitable for rough-terrain work.  Plus,  an axle across like that is vulnerable.  (The wider-stance version will trap each separate wheel with two struts,  and eliminate the long vulnerable axle between them.)

Figure 12 (photo 4097) – Narrow-Stance Wheels and Axle Assembly

I arranged the hydraulic cylinder mechanism to achieve 100 degrees of wheel strut travel in the 16-inch stroke of the cylinder.  The diameter is such that hydraulic systems operating anywhere from 300 psi to 2500 psi are all accommodated with no hardware changes.  The cylinder stroke travel limits are the actual stroke limits of the cylinder itself,  so no super-strong travel-limiting features are required of the wheel assembly design;  it only “sees” tool-raising loads. 

Figure 13 (4098) shows the fully-extended wheels-down position.,  and figure 14 (4100) shows the fully-retracted wheels-up position,  with the struts slightly-upswept at 10 degrees above the deck plane.  This allows greater ground clearance for the retracted wheels,  with the tool sliding on the ground in use.  

Figure 13 (photo 4098) – Wheels Fully Extended Down

Figure 14 (photo 4100) – Wheels Fully Retracted Up

There is a cross-connection valve needed in the plumbing assembly for the hydraulic cylinder.  This allows you to bleed off line pressures for coupling and uncoupling hydraulic hoses.  My prototype plumbing assembly,  shown in figure 15 (4101),  is built of hardware-store components rated “WOG” (water-oil-gas,  600 psig working pressure).  The hydraulic pump on my old antique tractor only produces around 300-400 psi,  so this was acceptable for my experimentation.  I still need to re-work this into real steel fittings and a hydraulic-rated valve,  for modern hydraulic systems now pushing 2500 psig.  

Figure 15 (photo 4101) – Cross-Connection Valve on Hose Manifold

In my very first tests,  I had not added the tow bar hitch assembly.  The tool came out of the shop as shown in figure 16 (4104).  At this point,  the chain bridle is still rigged as a lift sling.  The following video clip (4108) shows the very first tests of the wheel assembly,  under the awning at my shop.  My son did the filming.  You can see why the snout has two slider plates:  wheels-down it slides on the forward one,  wheels-up it slides on the aft one.  These need to slide flat,  so the snout doesn’t dig into the dirt. 

I had to modify my antique tractor into a modern two-way hydraulic system.  My hose connections are low near the left main wheel.  My hoses are about 16 feet long,  although for this setup,  I didn’t need that much.  For production,  I will use the same 20-foot length that Dave used.  You just coil up the excess on the tool deck and lash it there with a light,  breakaway cord.  Update 3-21-16:  you don't even need to lash it there.  They won't move far out of position.  If the coils move a bit too far,  you can always re-coil them next time you stop for something else.  What you watch for is fouling on the hydraulic wheel assembly,  or against your tractor tires in a turn.  You meed to do that anyway.  

My long feed hoses are half-inch,  with half-inch pipe-size fittings,  and quick-disconnect couplings that trap the hydraulic oil on both sides of the joint when disconnected.  The ports on the cylinder are “typical” at 3/8 pipe size.  Because of the short run,  I used 3/8 hoses from the cylinder to the manifold,  and transitioned to half-inch size at the manifold for a low-friction long run to the tractor.  The long feed hoses need to be of very tough construction,  because they will be seriously abused by dragging through the rough ground.  


Figure 16 (photo 4104) – Tool As Initially Tested

Video Clip 4108 – First Hydraulic Actuation Tests at Shop:

xxx unable to upload yet

Out in the pasture,  the first field tests were in an area where I had not followed-up properly,  so the few widely-separated cactus plants represented about 6 years’ regrowth.  This pasture was full of dead grass,  weeds,  and a ground-hugging invasive vine.  These items combined to cause debris to “bale-up” under the tool every so often.  As shown in the following video clip (4111),  this stuff eventually raises the tool up a little.  By the end of the clip,  we “step off” the bale,  a process far easier than slacking the chain and prying the tool up to manually remove the debris. 

It is also easy to see why I recommend doing more than one pass,  since the cactus pads are too often not torn free from their roots if you only drag across them once.  The other thing obvious from the video is that flexible stuff (live grass,  live weeds,  etc) just bends over as the tool passes;   it is the brittle stuff (cactus,  dead stuff) that breaks off.  That’s how and why the tool works. 

Video Clip 4111 – Initial Field Tests Out in the Pasture:

xxx haven't been able to load yet

After these tests,  I added a concept for a lighter-duty tow bar hitch to the snout.  This would not be suitable for actual dragging operations,  or even transport across rough ground.  This one is just for light-duty movement across relatively level,  smooth spaces.  As it turned out,  while useful for this purpose,  I don’t think a rig like this would be suitable for the market.  It allowed me to transport the tool slowly (solid wheels!) in my front yard without leaving even any snout drag marks in the grass.  Not everybody will need or want this,  so it’ll be an option,  when I do get it all worked out the way it needs to be. 

While rigging the tow bar,  I also addressed the problem of how to protect the hydraulic hose assemblies from damage should the tow bridle chain break.  There were two possibilities to pursue:  (1) breakaway fittings,  and (2) a safety chain like that used with trailers on the highway.  The breakaway fittings are available although more expensive,  and require a secure,  strong line rigged to pull the clamps you attach to the sleeves on the fittings. 

After thinking about it,  since you have to add the line anyway for breakaway fittings,  it was just about as easy to “add that line” as a simple safety chain.  So that’s what I did.  I attached it to the snout,  so that if the bridle broke,  you would be towing the tool by its snout.  The tool does not tow very stably that way,  it tends to wander around badly,  which should attract the tractor driver’s attention.  That way,  he can stop and repair the tow bridle chain,  but not have any hose damage to repair,  or any loss of hydraulic oil. 

Figure 17 (4122) shows the tool rigged for transport with the light duty tow bar.  This takes the form of a trailer hitch on a two-inch bar,  pinned at the length needed,  and pivoted at the rear for vertical swing,  to assist hitch-up.  It is strained from lateral motion by the forward “tower” trapping structure.  You back up under the hitch,  and then restrain the tow bar vertically with a chain looped around it.  When you put the wheels down,  it lifts the entire tool,  including the snout,  like a wheelbarrow.  The clearance is low,  but adequate for slow transport on relatively smooth ground.  Update 4-15-14:  this is not the practical,  producible towbar design that I finally ended up with.  

 Figure 17 (photo 4122) Tool Hitched for Transport


To unhitch,  first raise the wheels,  as in figure 18 (4123).  Undo the safety chain,  and slack the tow bar restraint chain,  as in figure 19 (4124).  Then release and stow the tow bar,  as in figure 20 (4125).  Hook up the tow bridle as in figure 21 (4126),  and take out its slack,  as in figure 22 (4127).  Hitch up the safety chain as in figure 23 (4128).  I like to duct tape chain hooks to prevent them from rattling loose,  as in figure 24 (4129).  Wheels-down / tool raised is the same as before,  see figure 25 (4130).  Wheels-up tool lowered is also the same,  as in figure 26 (4132).  Hitching back up for transport is the reverse.  

Figure 18 (photo 4123) – Unhitch:  First Raise the Wheels


 Figure 19 (photo 4124) – Unhitch:  Undo Safety and Slack Restraint


 Figure 20 (photo 4125) – Unhitch:  Release and Stow Tow Bar


 Figure 21 (photo 4126) – Unhitch:  Hook Up the Tow Bridle


Figure 22 (photo 4127) – Unhitch:  Take Out Bridle Slack


Figure 23 (photo 4128) – Unhitch:  Re-Hook Safety Chain

Figure 24 (photo 4129) – Unhitch:  Securing Chain Hook with Duct Tape


Figure 25 (photo 4130) – Unhitch:  Ready to Step-Over,  Wheels-Down


Figure 26 (photo 4132) – Unhitch:  Ready to Drag,  Wheels-Up

Conclusions So Far:

Transport wheels greatly ease the labor to clear debris or objects trapped beneath the tool.  This saves considerable time and effort in the field,  for those situations where the risks of trapped debris or objects are high.  This would include debris like barbed wire,  ground hugging vines,  dead weeds and grasses. 

The wheel assembly as tested has too narrow a stance,  as there is a lot of wobbling instability as it rolls over debris bales or rough ground.  The axle between the wheels is vulnerable to impact against rocks or other obstructions.  A wider stance with each wheel trapped between two struts is indicated. 

The light duty tow bar hitch assembly is too limited in strength,  and too limited in snout ground clearance,  to be a marketable product.  A fixed receiver and a hand-cranked jack on the tow bar are indicated,  more like what Dave used on his tools.  This is true in spite of the short life problems Dave had with those jacks in the field.  Update 4-15-14:  I finally solved this problem with a fixed towbar,  and a jackpoint on the snout tube for a small hydraulic bottle jack.  You just raise up the snout,  and back your trailer ball under the hitch on the towbar.  The bottle jack solves the crank-jack wearout problem for just about the same price.  

The safety chain method of protecting hydraulic hoses from damage if the tow bridle breaks seems to be very practical.  This part is ready to market. 

Near-Term Plans:

Rework the wheel strut assembly to a wide stance with two struts at each wheel.  There is no need to procure real shredder wheels for this. 

Redesign,  rework,  and retest the tow bar hitch assembly in a suitable alternate form,  based around a fixed receiver and a jack. 

Add installations of equipment fences and tow points.

Related Articles Posted on “Exrocketman”:

(date highlighted on this one)

Date.....…title/content
2-9-17....Time Lapse Proof It Works
............watch cactus being crushed and composted
7-30-15......New Cactus Tool Website
...................turnkey site for info,  photos,  videos,  purchases
1-8-15……Kactus Kicker Development
………………production prototype & 1st production article
1-8-14……Kactus Kicker: Recent Progress
…………..….testing a revised wheeled design (experimental)
10-12-13..Construction of the Tool
………………building a “Kactus Kicker” (plain tool)
5-19-13…….Loading Steel Safely
……………….transport and storage of materials
12-19-12…Using the Cactus Tool or Tools
……………...how the tool is employed (applies to any model)
11-1-12….About the Kactus Kicker
..…………….painting and rigging finished tools (plain tool)
12-28-11..Latest Production Version
………………new bigger snout and barge front (plain tool)

Update 1-18-2014

The next effort was to widen the stance or track of the wheels to improve stability.  I picked a nominal 5 foot track to match the wheel track of most smaller tractors.  This makes possible loading a tool onto the trailer without having to move the ramps to load the tractor.  The only requirement is a center ramp. 

As a caution:  do not simply drive the tractor onto the trailer with the tool hitched up behind.  Your trailer tongue load will be far too high.  You need the lighter item forward (the tool),  and the heavier item (the tractor) aft over the trailer axles.  Winch the tool up,  wheels-down,  dragging on its snout.  Then drive the tractor up afterward. 

I removed (1) the wheels,  then (2) the wheel strut assembly,  and then (3) the hydraulic hoses,  cylinder,  and manifold as a unit.  I used an angle grinder and an oxyacetylene torch to cut away the deck struts and hydraulic manifold mounting.  Then I cleaned up the tool deck smooth where they were mounted.

I then cut my wheel strut assembly on both sides of the center near the actuation arm,  leaving plenty of room for a second strut inboard of each existing wheel strut.  I cut extension pieces and splice rings to splice-out my wheel strut assembly to the wider stance,  as shown in Figure 1.  


 Figure 1 – (photo 4340) Cut-and-Splice Wheel Strut to Wider Stance with Jig

I used my fabrication jig so as to position the actuation arm and hinge line correctly to match the cylinder stroke and retract-arc geometry I had before,  and tacked it together.  My cut-and-spliced prototype is ugly;  production units will use one long piece of square tube all the way across.  Once tacked,  I hoisted the strut assembly onto sawhorses for complete splice welding as in Figure 2.

Figure 2 – (photo 4344) On Sawhorses for Splice Welding

I then welded-on the inboard wheel struts as shown in Figure 3.  These are spaced 6.25 inches to provide room for my prototype’s light-duty 15-inch diameter wheelbarrow wheels,  with a washer or two between the hub faces and the struts.  The production units use a real shredder “tailwheel”,  which is solid,  15-inch diameter,  1 inch axle bar size,  and a hub face-to-face dimension of 5.25 inches.  Production units will space the struts 5.75 inches (update 4-15-14: 6 inches worked much better,  and gave me a very practical way to secure wheel and axle to the legs with one single spring clip) apart to accommodate these wheels with washers.

Figure 3 – (photo 4346) Adding Inboard Struts

I matched locations with the on-deck struts and welded them in place at the wider stance.  This is shown in Figure 4.  Figure 5 shows the wheel strut assembly attached to the tool complete with wheels.  My wheelbarrow wheels use a 5/8-inch diameter axle bar,  production units will use a 1-inch axle bar,  but the basic assembly is the same,  you just drill bigger holes in the strut tube.

 Figure 4 – (photo 4348) Wheel Strut Assembly Welded to Tool Deck

 Figure 5 – (photo 4350) Wheel Strut Assembly Complete with Wheels

I used a spacer block at the original location of the portside on-deck strut to re-mount (by welding) the bracket that holds the hydraulic hose manifold.  This is shown in Figure 6.  Then I re-mounted (by bolt-up) the entire hose,  manifold,  and cylinder assembly as shown in Figure 7.

 Figure 6 – (photo 4352) Re-Mounting of Hydraulic Manifold Bracket

Figure 7 – (photo 4355) Re-Mounting the Hydraulics

In the field,  I revised the rigging of the hydraulic hoses to pass over the chain bridle and the cross chain.  You can see this in Figure 8.  You can also see the safety chain rigged from the snout barge front plate to the tractor drawbar assembly.  If the tow bridle breaks,  you are towing the tool by its snout,  which is not stable.  But,  you have not broken your hydraulic hoses and lost oil.  The misbehaving tool provides a warning to stop and fix the chain tow bridle.  Figure 9 is another view of the same features.

Figure 8 – (photo 4362) Hoses Re-Rigged over Chain Bridle Assembly

Figure 9 – (photo 4363) Another View of Rigged Tool

This thing worked exactly as expected:  very stable stepping off of debris bales or rocks (or other debris) hung-up underneath the tool.  Otherwise it did exactly the same job the narrow stance design did.  I will add a video clip as soon as one becomes available. 

Next on the list is reworking the tow bar transport hitch assembly into something market-ready.  That will be difficult.  Prototyping the other contemplated options should be pretty easy. 

Watch this space for further updates.  

Update 4-15-14:  The towbar hitch was revised to a fixed rig with a jackpoint and bottle jack,  on this experimental prototype.  It worked very much better,  with greatly simplified and reduced-effort hitch-up.  I got the towbar just about right,  but not the jackpoint.  Reworking that item on this experimental prototype has gotten rather impractical,  but the revised jackpoint design turned out to be very simple,  simple enough to just build it on the next tool.  

I still need to test out a trailer ball hitchpoint on this tool,  but that design is quite simple.  The tool retention fences are also very simple and need a trial on this tool,  as well.  Plus,  I will try out rainwater drain holes,  and if they work right,  I will make them standard on all production tools,  plain or hydraulic.  

These outcomes being so favorable,  I decided to build a real production pathfinder prototype,  to identify the last minor changes needed,  and to work out all the best production procedures and handling tooling.  And I built it!  This was a hydraulic tool with the towbar option installed,  complete with "proper" shredder solid wheels,  and a fully-qualified 2500 psi hydraulic system.  Except for some very minor changes,  it is the production design.  I will keep that one on hand for the rental business.  Watch this space for another article that documents the production prototype rollout.  

Update 7-30-15:  The new website is fully operational.  It has all the information,  photos,  and videos anyone could ever need.  It is a turnkey site for selecting,  customizing,  and purchasing a production tool.  Shipping is available,  so sales of plans have been discontinued.  Some additional parts and labor have been farmed out to appropriate vendors,  to adjust to higher production rates,  so prices posted previously are now obsolete.  Go to http://www.killyourcactusnow.com


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